Excess Ar in Some Metamorphic and Plutonic Rocks and Reduction of Thermal Neutron-induced ^<40>Ar by Cd Shielding
It is well known that, by the K-Ar dating, a reliable age cannot be obtained from a sample containing excess Ar. The ^<40>Ar-^<39>Ar method, on the other hand, has, potentially, ability to provive us geologically meaningful ages even for such samples with excess Ar. A Mowson charnockite...
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| Format: | Report |
| Language: | English |
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Tohoku University
1994
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| Online Access: | http://hdl.handle.net/10097/28521 https://tohoku.repo.nii.ac.jp/?action=repository_uri&item_id=47044 https://tohoku.repo.nii.ac.jp/?action=repository_action_common_download&item_id=47044&item_no=1&attribute_id=18&file_no=1 |
| Summary: | It is well known that, by the K-Ar dating, a reliable age cannot be obtained from a sample containing excess Ar. The ^<40>Ar-^<39>Ar method, on the other hand, has, potentially, ability to provive us geologically meaningful ages even for such samples with excess Ar. A Mowson charnockite from Antarctica shows a good example. In the ^<40>Ar-^<39>Ar dating, thermal neutron induced ^<40>Ar from 40K is one of the major source of errors in age calculation. Wrapping a sample with Cd foil is very effective in reducing this disturbing ^<40>Ar. |
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